Air brake mechanism



Feb. 4-, D c HESSIAN I AIR BRAKE MECHANI SM Filed Aug. 7, 1929 3 Sheets-Sheet l INVENTOR [9/1 is C ass z'aiz ATTORNEY/s Feb. 4, 1936. D. c. 'HESSIAN AIR BRAKE MECHANISM s sheets sneet 2 Filed Aug. 7, 1929 INVENTOR ATTO RN EY-S' Feb 1936- D. c. HESSIAN 233%939 AIR BRAKE MECHANISM Filed Aug. '7, 1929 5 Sheets-Sheet 5 4 I I INVENTOR f DeflmsC/fesszan wWM w MM ATTORNEYS Patented Feb. 4, 1936 UNITED STATES AIR BRAKE MECHANISM Dennis G. Hessian, Detroit, Mich; Anna Dalton executrix of said Dennis G. Hessian, deceased Application August 7, 1929, Serial No. 384,060

22 Claims.

IThis invention relates generally to air brake mechanisms and consists of certain novel features of construction, combinations and arrangements of parts that will be hereinafter more fully described, and particularly pointed out in the appended claims.

In the accompanying drawings:

Figure l is a diagrammatic View of air brake mechanism including a device embodying my invention;

Figure 2 is a vertical sectional View through the device embodying my invention showing a transitory, preliminary position assumed by the parts in applying the brakes;

Figure 3 is an enlarged detail section of one of the valve assemblies, showing a braking position thereof;

Fig. 4 is a view similar to Fig. 2, but showing the parts in running position with brake released.

Referring now to the drawings, I is a section of the main air line or conduit of a train, 2 is an auxiliary reservoir adapted to receive air from the section I, 3 is a brake cylinder adapted to receive air from the auxiliary reservoir, and 4 is a device embodying my invention for controlling the passage of air from the section I to the auxiliary reservoir 2 and to the brake cylinder 3.

As shown, the device 4 is bolted to one end of the auxiliary reservoir 2 and includes a casing 5 having chambers 6 and I respectively and having air passages 8, 9, I3, iI, I2, I3, and I4 respectively therein. Preferably the chamber 6 con.- tains the means for controlling the flow of air between the train line I and the auxiliary reservoir 2 and betwee i the auxiliary reservoir 2 and thebrake cylinder 3 and also contains the means for controlling a supplemental supply of air from the chamber 6 directly to the brake cylinder 3. The chamber i contains the means for controlling the main supply of air from the auxiliary reservoir 2 to the brake cylinder 3. The passage 8 supplies air from the train line section I to the chamber 6, the passage 9 supplies air from the passage 3 to the chamber 7, the passage It conducts air to and from the chamber I and auxiliary reservoir 2, the passage iI conducts air from the chamber 7 to the brake cylinder 3, the passage 2 is an exhaust or outlet passage from the chamher 6 to the-atmosphere, the passage I3 conducts air-from the chamber 5 to the chamber I, and the passage IQ conducts air from the chamber I to the chamber 6.

In the chamber 5 is a reciprocating valve I5 of tubular formation adapted to control the flow of air through the passage II and having a tapered lower end I5 engageable with a seat I6 of corresponding formation for controlling the flow of air through the passage 9. Preferably this valve I5 has an annular groove I! registerable with the passage II and adapted to permit or cut ofi the flow of air through the passage from the chamber 1 to the brake cylinder 3, and is provided at one side with an inverted L-shaped passage I8 for establishing communication between the longitudinally extending passage I9 within the valve and the passage II to permit air from the brake cylinder to enter the longitudinally extending passage I9. This valve I5 also has a restricted passage in its lower end to permit air from the passage 9 to flow to the longitudinally extending passage I9 to compensate for leakage out of the brake cylinder 3 when the brakes (not shown) are set. The upper end of this valve is reduced providing a shoulder 22 and is threadedly connected to a follower 23 that has a longitudinally extending passage 24 constituting an extension of the passage IS in. the valve and that is adjustably connected at its upper end to a piston 25. Preferably this follower 23 has a substantially Z-shaped passage 23 therein for conducting air from the passage 24 to a passage 21 in the piston 25, and the latter has a passage 28 opening into the chamber 6 below the piston and controlled by a valve 29. A plate 30 rests upon a shoulder SI of the chamber 6 and is provided with a tubular extension 32 that is sleeved upon the follower 23 and constitutes a trip for a bell crank lever actuator 33 for the valve 29. A coil spring 34 surrounds the follower 23 between the plate 39 and piston 25 and serves to move the piston 25, follower 23 and valve I5 upwardly.

Slidable in the passages I 9 and 24 and constituting an upward extension thereof is a tube 35 that is threaded in a second piston 36 and slidably engages the partition 31 between the chambers 3 and l. Preferably this partition 37 has a boss 38 upon which a cap 39 is threaded, and highly restricted communicating passages 49 and 4! are provided in the tube 35 and piston 33 respectively for conducting air from the chamber 3 to the cap 39. A ball 42 serves as a check valve in the passage 4| to prevent air from flowing from the passage 49 to the chamber 6, while a spring actuated valve 43 controls the flow of air from the passage 49 to the tube 35 and has a depending extension 43 that is adapted to close the passage 40. The pistons 33 and 25 divide the chamber 5 into an upper, an intermediate,

and a lower space. These are designated respectively 6a, 5b, and 60. An opening 55 is provided in the cap 35 that air from the chamber 7 may flow into the cap and thence into the tube 35, and a groove 3-5 is provided in the seat 55 to permit air from the cap 39 to flow into the tube 35. In this connection it will be noted that the passage .5 in the tube 35 has a branch. 48 that is adapted to be closed by the partition 31 when the tube 35 is in raised position, but is adapted to be opened when the tube 35 is in fully lowered position. In the present instance, the flow of air from the chamber 6 to the passage 53 is controlled by the piston 35 and a suitable check valve 4'! prevents air from flowing from chamber 1 to passage l3.

The chamber i is inverted L-shape in form and contains a tubular valve 58, a piston 5i, and a coil spring 52'. The spaces formed in the chamher 7 above and below the piston 5i are designated respectively to and 1b. As shown, the valve 55 controls the flow of air from the passage 9 to the space la and has a longitudinally extending passage 52, a transverse passage 53 for conducting air from the passage 9 to the longitudinally extending passage 52, and has a transverse passage for conducting air from the passage 52 to the chamber la above the piston 5|. This valve 56 is also provided at its lower end in communication with the passage 52 with a valve chamber 55 in which a valve 56 is located for controlling the flow of air from the passage 52 to the passage H leading to the brake cylinder. Preferably this valve 56 has a depending extension or stem 5'! that is engageable with the base 53 of the chamber I when the valve 58 is in lowermost position to unseat the valve 55 and permit air from the passage 52 to flow to the passage ii. Any suitable means such as the ball 58 may be used as a check valve to permit air to flow from the passage 9 to the passage 52 but to prevent its return. As shown, the piston 5i is threaded upon the valve 50 above the partition 3 and the spring 52' surrounds the valve 58 between this piston 5! and the shoulder 59 of the chamber 7.

When a brake system incorporating the described apparatus is being charged with air, as in starting a train on its run, pressure is progressively built up in the train pipe I and space 62) of each braking unit until the spring 34 is overcome, allowing the corresponding piston 25 to descend. The piston 36 of each unit if not already raised, will be uplifted well in advance of down travel of the piston since a slight preponderance of pressure below said piston as compared to that above it will effect such an uplift.

The piston 35, when raised, uncovers the passage l3 and further causes the valve 43 to seat upon and close the upper end of the tube 35. Hence air will flow freely up through the passage l 3 into the space '55, and from the latter through the port It into the space 512. Thus pressure will build up concurrently in the space 611, 1b and 6a, and will be equalized in these three spaces when charging is completed.

Assuming atmospheric pressure in the auxiliary reservoir and space "la at the commencement of charging, the piston 55 with its tubular valve member 56 will have been raised by the spring 52 to the position shown in Fig. 2, registering the ports 53- and 53a. pipe air, therefore, will flow, during charging, through the passage 9, raising the check valve and will enter the passage 52 through the aligned ports 53 and 53a, thence passing through the port 54, space Ta and passage ID to the auxiliary reservoir. Thus, while a charging pressure builds up in the spaces 612, lb and 6a, the same pressure accumulates in the auxiliary reservoir.

When the charging pressure reaches a value predetermined by resistance of the spring 34, the piston 25 is shifted to its lower limiting position, established by engagement of the valve head [5 with its seat 16. This prevents further flow in either direction through the passage 9, and also acts through the bell crank 33 to unseat the valve member 29.

Thus when the brake line is fully charged and the brakes are not applied, the pistons 36 and 5! are fully raised and the piston 25 fully lowered. Pressures are equalized in the spaces 61), 1b, and 6a and in the train pipe, and a slightly lower pressure prevails in the auxiliary reservoir. The valve 29 is unseated and the brake cylinder is vented by Way of passages ll, [8, I9, 26, 27, port 28, space 50, and outlet l2 to atmosphere. Also, seating of the valve 43 on the upper end of the tube 35 prohibits any loss of pressure through said tube from the space 1b.

The described position assumed by the parts after charging of the system is shown in Fig. 4 and is the normal or running position of the parts maintained during nonbraking travel of a train.

Assume now a service application of the brakes. Pressure in the train line and space 6b is thereby reduced according to the desired braking intensity. This reduction, for example, may range between three and twenty pounds, and to be effective, must decrease pressure in the space 6b below that exerted by the spring 34. Said spring, therefore, now elevates the piston 25 to its upper limiting position shown in Fig. 2. The check valve 41 prevents any downward escape of air from the space lb, and the superior pressure now prevailing in the spaces lb and 60. effects lowering of the piston 36, slightly beyond the position shown in Fig. 2. For a. service train pipe reduction, the piston 36 will descend sufliciently to unseat the valve member 43 from the tube 35 and to partially compress the springs 50, but the limiting lower position of said piston will not be reached.

Uncovering of the upper end of the tube 35 establishes a flow of air from the space 1b into the cap 39 through the port 45 and thence to the brake cylinder through the tube 35 and passage ll, whereby pressure in the space 11) rapidly drops below that in the auxiliary reservoir. Since this last mentioned pressure also prevails in the space 1a, the piston 5| is now shifted to its lower limiting position in which the valve 56 is unseated. This initiates a discharge of air from the auxiliary reservoir to the brake cylinder by way of the passage In, space To, port 54, passage 52, and passage H, whereby a brake-applying pressure is built up in said cylinder, and pressure in the auxiliary reservoir and space 7a is correspondingly reduced. When pressure in the space l'a thus becomes equalized with that in the space 1b, the piston 5| automatically rises, responsive to the spring 52' permitting the valve 56 to seat and discontinuing air delivery to the brake cylinder.

Thus it is apparent that the magnitude of brake cylinder pressure established by any reduction of train pipe pressure, is directly proportioned to the magnitude of such reduction.

It is to be noted that uncovering of the tube 35 by the valve member 43 can reduce pressure in the space 1b l tl s we the-penn n in the space 6b, since when pressure-in the latter space acquires a slight preponderance, thepi ston 36 will rise and reseat the valve 4.3; on the tube 35. In so rising, said piston will uncover the passage l3 and allow a sufiicient slight upward transfer of air through said passage to again equalize pressures in the spaces; 6b, 1b, and 5a..

Because of its highly restricted nature, the passage 45!, 4| does not interfere with the operation, as so far described. Under nombraking conditions said passage is closed by the, needle valve 43', since the member 43 carrying, said needle valve is then seated upon the tube, 35.

When, through a train pipe air reduction, the piston 36 and tube are lowered, uncovering the upper ends of said tube andof-the passage, 4|, air discharges in a restricted flow from the space 6b to the tube 35, expediting the,,.pressure reduction. Until the piston 25 rises, such air. vents to the atmosphere, by, way. of theport 28. After rise of the piston 25 and-resultant seating of the valve 29, such air is delivered into the brake cylinder. The describedflow throughthe passage 40, 4|, when the valve member. 43 is clear of the tube 35, will befar less than the concur.- rent discharge to said tube from the. spaces. 1?) and 6a (communicating at I4), and hence will not prevent the pressure in said spacesfrom falling rapidly below that in the space 61), tov initiate cutting ofi of the reservoir air delivery. to the brake cylinder.

The port it maybe noted, is not uncovered unless the piston 36 descends to itsv extreme or limiting lower position. This occurs only responsive to an emergency reductionof train pipe pressure. the resulting differential between the measures in spaces 6a and 6b being oisuchmagnltude as to fully overcome the. springs. 60. Under such conditions, air discharges from. thespace 6a (and communicating space 11)) to. the passage 40, 4| as well as from the space'lib, sdthat the application of the brake is very considerably expedited.

One advantage derived from the described valve mechanism is its adaptability. to permit a recharging of the main air line andthe auxiliary reservoirs of a train during a serviceapplication of the brakes. without releaseof the brakes. or diminution of the braking pressure. The re charging air will enter the chamberithr'ough the passage 8 and will also reach the. auxiliary reservoir by way of passages 9. 53, 52', 54, and i0. Recharging will be stopped short of. such pressure as would overcome thespring 34, and vent the brake cylinder through resultant lowering of the piston 25. Thus, for example, if train line and auxiliary reservoir pressurewere reduced from 70 to pounds in effectingan application of the brakes, and 701* pressure was required to overcome the spring 34. it would be possible to recharge the train line and auxiliary reservoirs to a pressure only slightly below without effecting a release of the brakes,

This advantage which is not derivable from ordinary air brake valves is particularlyidesirablie in descending long grades, under braking retardation.

The auxiliary reservoirs are adapted to' be charged only up to a certain limitingpressure determined by resistance of the spring 3,4 This permits the train pipe, at its head end, tobe overcharged sufficiently to charge the rear, as well as the front auxiliaries up to the pr edeterr mined. imi -l h e char lb at a an amount in excess of normal train pressure such as toi bring the rear end auxiliaries up to the yielding point of the corresponding springs 34. The length of the train will ordinarily determine the requisite amount of overcharge, since the differentialbetween front and rear end train pipe pressure will be generally proportionate to the train length. After so establishing normal uniform pressure in all of the auxiliaries, (that is to say, the pressure under which the spring 34 yields) the train pipe pressure may be reduced back to normal, without effecting an application of'the brakes. Normal train pipe pressure will ordinarily slightly exceed the pressure required to overcome the springs 34.

As is well known, this is not possible with equipment now standard. which would involve a setting of brakes on reduction of an overcharge and which in case of an overcharge in the train pipe would involve, at any point, the same overcharge in the auxiliaries.

This feature of applicants valve mechanism insures a substantially uniform pressure applied to. the brake cylinders throughout the length of a train.

The retaining valves now commonly provided on each car are further unnecessary with the herein-disclosed system.

"While it is believed that from the foregoing description the nature and advantages of the invention will be readily apparent, I desire to have it understood that I do not limit myself to what is herein shown and described and that such changes may be resorted to when desired as cylinder, means for controlling the passage of air from the first chamber to the second chamber, and means associated with said last mentioned means for controlling the passage of air from the second chamber to the brake cylinder.

2. In a device of the class described, a casing having achamber adapted to be supplied with air from the main train line conduit, a second chamber adapted to receive air from the first chamber, means for conducting air from the second chamber to a brake cylinder, auxiliary means for conducting air from the second chamber to the brake cylinder, means in the first chamber for controlling the passage of air therefrom to the second chamber, means operable by said last mentioned means for controlling the passage of air from the second chamber through the first mentioned conducting means to the auxiliary reservoir, and means under the control of the first mentioned controlling means for controlling the passage of air from the second mentioned chamber through the auxiliary conducting means to the brake cylinder.

3 111 a device of the class described, a casing having a chamber adapted to be supplied with air from the main train line conduit, a second chamber adapted to receive air from the first chamber, means for conducting air from the second chamber to a brake cylinder, auxiliary means for conducting air from the second chamberto the brake cylinder, means in the first chamber for controlling the passage of air therefrom to the second chamber, means in the second chamber for controlling the passage of air therefrom to the auxiliary reservoir, and means under the control of the first mentioned controlling means for regulating the passage of air from the second chamber through the auxiliary conducting means to the brake cylinder.

4. In a device of the class described, a casing having a chamber adapted to receive air from the main train line conduit, a second chamber adapted to receive air from the main train line conduit, means for conducting air from the first chamber to the second chamber, means for conducting air from the second chamber to the first chamber, means for conducting air from both chambers to a brake cylinder, means associated with the last mentioned means for conducting air from the brake cylinder through the first mentioned chamber to the atmosphere, and means under the control of the last mentioned conducting means for controlling the passage of air from the brake cylinder to the atmosphere.

5. In a device of the class described, a chamber adapted to receive air from the main train line conduit, means for conducting air from said chamber to a brake cylinder including, telescopically arranged members, one of said members having a passage extending longitudinally thereof and in communication with said chamber, and means for controlling the passage of air from said longitudinally extending passage to said member including a valve engageable with said member and having an extension engageable with the walls of said passage.

6. In a device of the class described, a casing having a chamber adapted to receive air from the main train line conduit, means including telescopically arranged tubular members for conducting air from said chamber to a brake cylinder, and means including said telescopically arranged members for conducting air from the brake cylinder to the atmosphere, and means for controlling the passage of air from said members to the atmosphere including means operable upon movement of one of said members relative to another of said members.

7. In a valve mechanism for air brakes, a pair of pistons movable to and from each other, a cylinder forming a pressure chamber between said pistons and forming with one of said pistons a chamber vented to the atmosphere, means establishing a train pipe connection to saidpressure chamber, means jointly carried by said pistons providing a passage for delivering air from said pressure chamber to a brake cylinder, means for controlling such delivery through travel of one of said pistons, said passage having an opening into said vented chamber, and means for controlling said opening through travel of the other piston.

8. In a valve mechanism for air brakes, a pair of pistons movable to and from each other, a cylinder forming a pressure chamber between said pistons, said pistons being spaced from the cylinder ends to form two end chambers, means establishing a train pipe connection to said pressure chamber, a passage for conducting air from said pressure chamber to one of said end chambers controlled by the piston separating said chambers, the other end chamber being vented to the atmosphere, means preventing return fioW of air through said passage, a passage for debrake cylinder, means for controlling such delivery through travel of one of said pistons, and means for controlling connection of the last mentioned passage with said vented end chamber, through travel of the other piston.

9. In a valve mechanism for air brakes, a pair of pistons movable to and from each other, a cylinder forming a pressure chamber between said pistons, and forming with one of said pistons a chamber vented to the atmosphere, means establishing a train pipe connection to said pressure chamber, a passage for delivering air from said pressure chamber to a brake cylinder, means for controlling such delivery through travel of one of said pistons, and means for controlling connection of said passage to said vented chamber through travel of the other piston.

10. In a valve mechanism as set forth in claim 9, a spring opposing a predetermined resistance to travel of one of said pistons from the other.

11. In a valve mechanism for air brakes, a pair of pistons movable to and from each other, a cylinder forming a' pressure chamber between said pistons, and forming with one of said pistons a chamber vented to the atmosphere, means establishing a train pipe connection to said pressure chamber, a pair of telescoped tubular members, one carried by each of said pistons and jointly forming an air passage, means establishing a brake cylinder connection to said passage, means controlled by one of said pistons for establishing or cutting off a delivery of air from said pressure chamber to said passage, and means carried by the other piston for controlling connection of said passage to said vented chamber.

12. In a valve mechanism for air brakes, a pair of pistons movable to and from each other, a cylinder forming a pressure chamber between said pistons, and forming with one of said pistons a chamber vented to the atmosphere, means establishing a train pipe connection to said pressure chamber, a tubular member carried by one of said pistons extending through said pressure chamber and slidable in the other piston, said member forming an air passage, means establishing a brake cylinder connection to said passage, a valve controlling air delivery from said pressure chamber to said passage, and under control of the piston carrying said tubular member, and means for venting said brake cylinder connection controlled by the other piston.

13. In a valve mechanism for air brakes, a pair of pistons movable to and from each other, a cylinder forming a pressure chamber between said pistons, means establishing a train pipe connection to said pressure chamber, a passage for delivering air from said pressure chamber to a brake cylinder, means for controlling such delivery through travel of one of said pistons, said passage having a vent opening for relieving brake cylinder pressure, means for controlling said vent through travel of the other piston, an auxiliary reservoir, a conduit establishing an air delivery connection to said reservoir from the train pipe, control means for the last-mentioned connection carried by one of said pistons, means for delivering auxiliary reservoir air to the brake cylinder, and control means for said delivery means carried by one of said pistons.

14. In avalve mechanism for air brakes, a pair of pistons movable to and from each other, a cylinder forming a pressure chamber between said pistons, means establishing a train pipe connection to said pressure chamber, a passage for livering air from said pressure chamber to adelivering air from said pressure chamber to a brake cylinder, means for controlling such delivery through travel of one of said pistons, said passage having a vent opening for relieving brake cylinder pressure, an auxiliary reservoir, means for delivering train pipe air to said reservoir, means carried by the other piston for controlling said vent opening and for controlling the lastmentioned delivery means, and means for delivering auxiliary reservoir air to the brake cylinder.

15. In a valve mechanism for air brakes, a casing having a vent opening, a train pipe, a brake cylinder, a piston operating in said cylinder controlling communication between said train pipe and brake cylinder, and a second piston operating in said cylinder and controlling communicaton of said brake cylinder with said vent open- 16. In a fluid pressure brake, the combination with a train pipe, an auxiliary reservoir, and a brake cylinder, of a valve device comprising a casing and two pistons movable to and from each other in said casing, said pistons and casing jointly forming a fluid pressure chamber, means placing the train pipe in communication with said chamber, and means for controlling fluid delivery from the train pipe to the auxiliary reservoir and from said reservoir to the brake cylinder jointly by travel of said pistons.

1'7. In a fluid pressure brake as set forth in claim 16, a spring imposing on one of said pistons a predetermined resistance to pressure in said chamber.

18. A fluid pressure brake comprising a cylinder, a fluid chamber, and a. partition between said cylinder and chamber, a train pipe connection to the cylinder, 2, piston positioned in the cylinder between the partition and train pipe connection, and reciprocatory to and from the partition, a passage for delivering train pipe fluid to the chamber, a valve resisting return flow through such passage, a brake cylinder, a tubular stem carried by the piston and slidable in the partition, and adapted to deliver fluid to the brake cylinder from the chamber, and a valve in said chamber adapted to seat on the stem to out off fluid discharge to the brake cylinder from the chamber and engageable with the partition to uncover the stem, upon retraction of the piston from the partition.

19. A fluid pressure brake as set forth in claim 18, the stem extending through and axially of the cylinder.

20. A fluid pressure brake as set forth in claim 18, said stem having an abutment limiting approach of the piston to said partition.

21. A fluid pressure brake as set forth in claim 18, the cylinder having an outlet to the passage for delivering train pipe fluid to said chamber.

22. In a fluid pressure brake as set forth in claim 18, an element carried by said piston and engaging said partition to limit retraction of the piston from the partition.

DENNIS C. HESSIAN. 

